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BlkSwan03@aol.com wrote: > > Does anyone on the list use compression software (like Stuffit Deluxe) to > squeeze as much as you can onto your drives? Does this create problems or > mess up quality? Stuffit - a lossless compression method - does not alter your data. Many people use it (or PKZIP on the PC) when they archive seldom-used files. When you are compressing images with an image editing program, JPEG compression will definitely alter data (lossy compression). If you have an image in JPEG format, and you resave it as JPEG, the data alteration compounds. JPEG is a good compression algorithm, and it tries to only throw away data that is least perceptible to the human eye, but it does permanently change the image each time it's used. Therefore, use it once, and only once. You will see many images on CD collections that are supplied in JPEG format. This is fine, since the images are usually very high resolution, and are intended for printing at resolutions of 200 ppi or higher. At these settings, the effects of JPEG are barely noticeable, if at all. If you make any alterations to such an image, you should resave it in a format which uses no compression, or at least one that uses a lossless method. LZW compression is an example of lossless compression. Where JPEG will catch up tp you is when it is applied to an image which will be viewed on-screen, at screen resolution. In that case the different compression ratios have noticeably different effects on the viewing quality of the image. Ken Kehl ellipsis design ____________________________ Luck comes in two flavors... ____________________________ -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Please: Stay on topic. Trim quoted messages. http://www.leben.com/lists for list instructions.
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